Fig. 1. Analysis of nuclear and spindle pole movements. (A) DIC images of live let-99 (top row) and let-99; dhc-1(RNAi) (bottom row) embryos recorded by time-lapse video microscopy. Arrowheads mark the centrosomes and relative time points are indicated in the top left-hand corner of the images. Scale bar: 10 µm. (B) Traces of spindle pole position in representative one-cell embryos from metaphase to cytokinesis onset (time 0). 0% egg length indicates the anterior tip of the embryo; the posterior tip would be at 100%. Arrows in wild type (N2) and par-3 mark the time at which spindles began elongating and spindle poles started to oscillate; the most vigorous oscillations occurred in the middle of the elongation phase. Arrow in let-99 indicates the time at which nuclear/spindle rocking ceased.